The present invention relates in general to a high density modular electrical connector and, more particularly, to a self-centering modular electrical connector which can be readily adapted to different contact counts and configurations.
An interface connector is used to connect integrated circuit (IC) chips and IC chip carriers to known circuit boards or the like. IC chips and IC chip carriers typically have a plurality of pins or leads in an array on a surface thereof. The pins are received by associated passages in an interface connector which is then mounted to a circuit board, thereby putting the IC chips and IC chip carriers in electrical contact with the circuit board.
An adequate interface connector between an IC chip and other circuitry continues to be a challenge. The number of closely spaced leads which come from the chip must be able to interface in a relatively high density configuration. However, the wide variety of chip configurations that are available does not always lend itself to making a uniform connector in that there may be varying numbers of leads and various arrays of leads. The known connectors have generally been useful only for single IC chip configurations and are not readily adaptable for expansion and/or revision. Typical limitations to area array components include coefficient of thermal expansion (CTE) mismatch, coplanarity or moldability problems (which is the ability to repeatably manufacture a component using a molding process such as thermoplastic molding), and high mating forces and component alignment.
Regarding the problem of CTE mismatch, area array components such as connectors, devices, and packages, are limited in size based on the materials that form the various components. The different CTEs and the size of the components affect the performance and reliability of the electrical connections after thermal cycling. The greater the differential displacements created by CTE mismatch during thermal changes, the greater concern for the electrical integrity of the system.
Regarding mating force, simultaneous parallel mating of the contacts can cause a high peak mating force when compared to other mating techniques. In high density applications, the connector housing and substrate materials may not be sufficiently rigid to adequately accommodate these peak forces.
Although the art of connectors is well developed, there remain some problems inherent in this technology. Therefore, a need exists for a modular interface connector that overcomes the drawbacks of conventional connectors.
The present invention is directed to a modular construction of connectors for reducing the effects of the differential coefficient of thermal expansion of the connectors and the underlying circuit board. Each connector of the modular construction in accordance with the present invention is mounted on a known circuit board or the like and could receive therein an integrated circuit chip carrier or could mount to another board. The present invention uses the principle of solder surface tension and self-centering characterized in ball grid array (BGA) surface mount technology to form an array connector having multiple components that form a larger array pattern or group of arrays.
The foregoing and other aspects of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.